What is Labrador Tea?
Labrador tea is a low evergreen shrub from cold northern bogs. Its dried leaves are brewed as a herbal tea. In French Canada it is called thé des bois, and in English it is often called marsh tea.
The name covers more than one plant. Ledum latifolium is an old botanical name for Rhododendron groenlandicum. A look-alike relative, Ledum palustre, holds much more of the plant's toxic oil.
Folk and Eclectic healers in North America used the tea for coughs, colds, upset stomach and itchy skin. Human evidence for any of these uses is very thin. Long use in a tradition is not proof that a remedy works, and it is not proof that it is safe.
This page treats Labrador tea as a caution herb. It is drunk as a beverage in parts of Canada, but strong brews, large amounts and mistaken plant identity have caused real harm.
How does Labrador Tea work?
No one has shown in people how Labrador tea works, or that it works at all.
Most of what is known comes from lab dishes and animals. In cell studies, leaf extracts appear to lower markers of swelling. In test tubes they slow the growth of some bacteria and fungi.
In mice fed a high-fat diet, extracts appeared to improve how the body handled blood sugar. That work grew out of research on Cree traditional medicine in Canada. Whether the same thing happens in people is not known.
The leaf oil contains ledol. In animals, ledol acts on the brain. It can calm at low amounts and poison at higher ones.
That split is the main reason brew strength matters. A quick steep pulls out little oil. A long steep, a boiled-down brew, or a handful of leaves pulls out much more.
What forms does Labrador Tea come in?
Dried leaf for tea is by far the most common form.
- Loose dried leaf, sold in bags by wild-herb suppliers.
- Tea bags, often blended with other northern herbs.
- Tinctures, which are alcohol extracts sold by some herb shops.
- Essential oil, sold for scent only. It must never be swallowed.
- Fresh leaves picked by foragers, which carry the highest risk of the wrong plant.
Labelling is often loose. Packages may say Ledum, marsh tea or muskeg tea without naming the exact species. Ask the seller which plant it is and where it was picked.
Where it comes from:
Indigenous peoples across northern North America used the leaves as a daily drink and as a medicine. Uses recorded by later writers included coughs, colds, stomach trouble and washes for itchy skin.
Settlers took up the drink too. One story ties it to colonial boycotts of imported tea, though the record is mixed.
Nineteenth-century Eclectic physicians in the United States listed Ledum for coughs and skin complaints. Their notes were based on case reports and custom, not on trials.
The dried leaf was also strewn among clothes to keep moths and fleas away. That use points at the strength of the oil.
Who should avoid Labrador Tea?
- Do not use if you are pregnant, or if you are trying to become pregnant. The plant has a long folk reputation for causing miscarriage.
- Do not use if you are breastfeeding.
- Never give it to babies or young children.
- Do not swallow the essential oil, in any amount, ever.
- Do not drink strong, long-steeped or boiled-down brews.
- Do not use if you have kidney disease.
- Do not use if you have liver disease.
- Do not use if you have a heart rhythm problem, or if you take heart medicine such as digoxin or a beta blocker.
- Do not use if you take sedatives, sleeping pills or opioid painkillers.
- Do not use if you take lithium.
- Do not use if you have epilepsy or have had a seizure.
- Do not drink it before driving or using machines, because it can make you sleepy.
- Do not use it in the two weeks before surgery, and tell your surgical team if you have been using it.
- Never brew leaves you picked yourself unless an expert has named the plant. Ledum palustre, the stronger marsh species, looks similar and is more toxic.
When should you see a doctor?
Stop drinking it and call a doctor if you get nausea, cramps, a headache or a rash that does not settle.
Get urgent medical help for these signs:
- Confusion, odd thoughts or trouble staying awake.
- Trembling, twitching or a seizure.
- A slow, racing or irregular heartbeat.
- Fainting, or feeling you are about to faint.
- Repeated vomiting or severe stomach pain.
If a child drinks it, call a poison centre straight away, even if the child seems fine.
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